Segmentation of views for simplified navigation on limited device

ABSTRACT

In one form, a method, for creating multiple segments of source information for presentation on a device having a limited size display screen, includes generating a first derivative file describing first presentation material. The derivative file is derived from a first copy of a master style sheet file. The master style sheet specifies a style of displaying the source information. The source information includes a plurality of attributes, of which a first set of attributes are included in the first derivative style sheet file. A second derivative file describing second presentation material is derived from a second copy of the master style sheet file. A second set of attributes included in the source information are included in the second derivative file. The first presentation and second presentation materials are generated responsive to the source information and the respective first and second derivative files.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to displaying information on adisplay screen, and more particularly to a web-browsing navigationaltool for handheld computerized devices.

[0003] 1. Related Art

[0004] With the advent of the Internet, it is increasingly common todisplay information, particularly Internet web pages, with connected,limited devices (“CLD's”) that are highly portable, and thereforelimited in size and computational power. Typical examples of CLD'sinclude small, handheld computerized devices such as a personal digitalassistant (“PDA”) with or without built-in communication function,cellular telephone, and two-way pagers. Due to size and battery powerconstraints, the processor included in a CLD typically provides lesscomputational power than a desktop computer, and therefore has limitedresources for performing tasks such as processing instructions, anddisplaying information. Of course, the display screen for a CLD istypically smaller than the size of a desktop computer display screen.Therefore there is an increasing need to efficiently utilize the limitedresources available to a CLD. Additionally, it may be desirable toprovide a web-browsing tool for the small sized display screen of a CLDto navigate and display information efficiently in response to userinputs.

[0005] Referring to FIG. 1, information 100 is shown, displayed in asingle view, generated by a conventional web browser for a desktopdisplay screen 105. According to prior art, a display screen 110, for aCLD 190, is also shown, displaying a portion 112 of information 100displayed on display screen 105. Horizontal scroll bar 115 and verticalscroll bar 120 are used to control the relative position of displayscreen 110 within information 100. While it is possible to view all ofinformation 100 on display screen 110 by moving small display screen 110around within information 100, this arrangement is neverthelessproblematic. For example, it may be difficult to correlate a first pieceof information 100 displayed with in display screen 110 in a firstposition with another piece of information 100 located several rowsand/or columns away that is displayed with in display screen 110 in asecond position.

[0006] The World Wide Web Consortium (“W3C”) has developed standards forthe world wide web (“WWW”) that promote further evolution of the WWW andensure interoperability. W3C standards such as Extensible MarkupLanguage (“XML”), Extensible Stylesheet Language (“XSL”) and XSLtransformations (“XSLT”) are well known for generating informationdisplayed by a browser.

[0007] As stated above, it is common to display information, such asinformation 100, in a web page format. Referring to FIG. 2, aspects ofsuch formatting are illustrated, according to prior art. As shown inFIG. 2, an XSLT processor 220 adds styling information in the form of anXSLT style sheet file 230 to an XML source document 210, transformingsource document 210 into a resulting HTML document 240. Alternatively,the resulting document 240 may be prepared by using otherpresentation-oriented formats such as XHTML, PDF or scalable vectorgraphics (“SVG”). Although referred to as a “processor”, XSLT processor220 is a software program.

[0008] From the above it should be appreciated that there is anincreasing need to format information for presentation on a devicehaving a limited display size, and that it is particularly useful to doso in a manner that conforms to browser-related standards.

SUMMARY OF THE INVENTION

[0009] The forgoing need is addressed by the present invention,according to one aspect of which a method is provided for creatingmultiple segments of source information for presentation on a devicehaving a limited size display screen. The method includes generating afirst derivative style sheet file describing first presentationmaterial. The first derivative style sheet file is derived from a firstcopy of a master style sheet file. The master style sheet specifies astyle of displaying the source information. The source informationspecified by the master style sheet exceeds an amount which the limitedsize display screen is capable of displaying in one view. The sourceinformation includes a plurality of attributes, out of which a first setof attributes are included in the first derivative style sheet file. Asecond derivative style sheet file describing second presentationmaterial is derived from a second copy of the master style sheet file. Asecond set of attributes included in the source information are includedin the second derivative style sheet file. The first presentationmaterial is generated responsive to the source information and the firstderivative style sheet file. The second presentation material isgenerated responsive to the source information and the second derivativestyle sheet file.

[0010] In another aspect, the source information specified by the masterstyle sheet exceeds an amount of information capable of being displayedby the device in a single view. The source information includes a firstsegment of information associated with the first set of attributes and asecond segment of information associated with the second set ofattributes. The first presentation material is for generating a firstview the first segment on the device and the second presentationmaterial is for generating a second view of the second segment on thedevice. The device is capable of concurrently displaying, in the firstview, all of the first segment of information, and is capable ofconcurrently displaying, in the second view, all of the second segmentof information.

[0011] Additional aspects, objects, advantages and other forms of theinvention will become apparent upon reading the following detaileddescription and upon reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1, described above, is a web browser generated display,suitable for viewing on a large display screen, according to the priorart.

[0013]FIG. 2, described above, is a block diagram illustrating a methodto generate a web display using XML and XSLT standards, according to theprior art.

[0014]FIG. 3 is a block diagram for generating a web display for a CLDhaving small display screen, according to an embodiment of the presentinvention.

[0015]FIG. 4 is a block diagram for deriving a derivative style sheetfrom a master style sheet, according to an embodiment of the presentinvention.

[0016]FIGS. 5A, 5B and 5C illustrate a series of optimized web pages,according to an embodiment of the present invention.

[0017]FIG. 6 is a flow chart illustrating a method for restyling a webpage to an optimized web page is shown.

[0018]FIG. 7 illustrates a computerized device to implement method orapparatus aspects of the present invention, according to an embodiment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0019] The claims at the end of this application set out novel featureswhich applicant believes are characteristic of the invention. Theinvention, a preferred mode of use, objectives and advantages, will bestbe understood by reference to the following detailed description of anillustrative embodiment read in conjunction with the accompanyingdrawings.

[0020] Referring to FIG. 3, a block diagram is shown illustratingaspects of displaying information on a CLD having a display screen oflimited size, in accordance with an embodiment of the present invention.In the embodiment, the CLD is enabled to perform web browsing. That is,a user is able to view portions of information 100 (FIG. 1) formatted asHTML documents using a web browser program running on the CLD.

[0021] Referring to FIG. 1, for example, a CLD user may wish to access aremote web server to retrieve a service request record 140 from adatabase of information 100. Service request record 140 may be definedto include relevant data and/or information describing a servicerequest. In the illustrated example, each service request record 140 hasthe following attributes: unique problem number 130, status 145, duedate and time 150, severity 155, group user 160, location 165,contact/company 170 and problem description 175. Unique problem number130 attribute may also be described as a primary key to access thedatabase.

[0022] Referring back to FIG. 3, in the embodiment information 100(FIG. 1) is segmented into multiple views. The number of views may beconfigured based on design considerations such as size of CLD displayscreen 110 (FIG. 1). In this embodiment, a first derivative XSLT stylesheet file 310, a second derivative XSLT style sheet file 320 and anoptional additional derivative XSLT style sheet 330 are derived from amaster (also known as a “parent”) XSLT style sheet file 230 (FIG. 2)describing information 100. The process of deriving a derivative (alsoknown as a “child) style sheet from a master style sheet may beimplemented manually or may be automated by a computer program, and willbe further described in connection with FIG. 4 below.

[0023] XML source document 210 provides source information, e.g.,information 100, which typically includes a number of tagged attributes.For example, information 100 includes information having a number oftagged attributes such as in FIG. 1—problem number 130, status 145, anddue date 150 described in service request record 140.

[0024] In one aspect, master XSLT style sheet file 230 specifies thestyling and/or the layout of the HTML document 240 (FIG. 2), includinginformation 100, optimized for display by a web browser on the displayscreen 105 (FIG. 1) of a desktop computer. Accordingly, the informationspecified by the master XSLT style sheet file 230 exceeds an amountwhich the CLD display screen 110 is capable of displaying in one view.To optimize for the CLD display screen 110, the information from thesource document 210 is segmented by processor 220, responsive to stylesheets 310, 320 and 330, into HTML documents 340, 350 and 360, which areoptimized for viewing on the CLD display screen 110. This advantageouslyprovides improved navigation. It also conserves bandwidth, i.e., fordownloading data to the CLD.

[0025] Referring to FIG. 4, in one embodiment, the process of deriving aderivative style sheet includes making a number of copies 470 of themaster XSLT style sheet file 230. First derivative XSLT style sheet file310 is generated from a first one of the copies 470 of master XSLT stylesheet file 230, and specifies a first set of attributes 425 which isassociated with a first portion (or segment) of the source information.Likewise, second derivative XSLT style sheet 320, is generated from asecond one of the copies of master XSLT style sheet file 230, andspecifies a second set of attributes 435 associated with a secondportion of the source information. Of course, additional derivative XSLTstyle sheets, such as style sheet 330 may be generated from additionalcopies of the master style sheet, as shown in the embodiment.

[0026] As previously stated, the source information from source document210 and the derivative style sheets 310, etc. are processed with XSLTprocessor 220, which generates respective presentation-style, e.g.,HTML, documents 340, 350, etc. for generating respective views of theinformation portions on the CLD. Note that the CLD is capable ofconcurrently displaying the entire first portion of the information,i.e., information specified by the first style sheet 310, on displayscreen 110 in the first view, the entire second portion in the secondview, etc.

[0027] The process of generating first derivative XSLT style sheet file310 includes deleting one set of the attributes 440 from the first copyof the master style sheet and adding a link attribute 450 referring tothe second derivative XSLT style sheet 320, so that the first view ondisplay screen 110 includes a link for navigating from the first portionof the information to the second portion of the information. Likewise,the process of generating second derivative XSLT style sheet 320includes deleting a second set of the attributes 460 from the secondcopy of the master style sheet and adding link attributes 450 referringto first and third derivative XSLT style sheets 310 and 330 so that theview on display screen 110 of the second portion of the informationincludes links for navigating from the second view to the first andthird views.

[0028] Note that the two views associated with style sheets 310 and 320have some information in common and some disparate information. That is,a certain key one of the attributes, problem #130, is included in boththe first and second segments of the information, i.e., is not deletedin either copy of master XSLT style sheet 230, so that CLD displays theinformation for this key attribute in both the first and second views.This provides some context for the user tying the two views together.Note also that some of the attributes 440, which are deleted in theprocess of generating first derivative XSLT style sheet 310, areincluded among attributes for second derivative XSLT style sheet 320.Likewise, some of the attributes 460, which are deleted in the processof generating second derivative XSLT style sheet 320, are included amongattributes for first derivative XSLT style sheet 310, so that the firstand second views include some disparate information, i.e., informationthat is not in common between the two views.

[0029] Referring now to FIGS. 5A, 5B and 5C, a series of optimized webpage displays are illustrated, according to an embodiment. Navigationamong the displays is responsive to receiving scroll commands, as willbe explained. Referring first to FIG. 5A, HTML document 340 (FIGS. 3 and4) is displayed on CLD display screen 110 in first view 510. Included infirst view 510 is a portion of the information 100 (FIG. 1). That is, aportion of the information 100 associated with the first set ofattributes 425 (FIG. 4) is displayed in view 510. This includes valuesfor the attribute which each view has in common, i.e., the problemnumber, e.g., “00004706.” It also includes values for each of theattributes 425 (FIG. 4), i.e., status, date and severity.

[0030] For navigational purposes, first view 510 also includes a currentpage number and a total number of pages, i.e., “page 1 of 3.” The view510 also includes the link 450 (FIG. 4). In response to a CLD userclicking on a “forward,” i.e., “next,” arrow of the horizontal scrollbar 115, the link attribute 450 (FIG. 4) is activated, calling up secondview 520. The “previous” arrow does not have a link in the first view510.

[0031] Referring to FIG. 5B, in response to the link 450 being activatedfrom the first view 510 (FIG. 5A), HTML document 350 is displayed on theCLD display screen 110 in the second view 520. This view 520 does notshow status, date and severity attributes which were included in firstview 510. Likewise, the second set of attributes 435 (FIG. 4), whichincludes group user, location and contact, is displayed in the secondview 520, but not in the first view 510.

[0032] Once again, in the second view 520 for navigational purposes thevalue for the current page number and of total number of pages isdisplayed, i.e., “page 2 of 3.” The second view 520 includes links 450(FIG. 4) to the first and third views. In response to a CLD userclicking on the “next” arrow, one of the link attributes 450 (FIG. 4) tostyle sheet 330 (FIGS. 3 and 4) is activated, calling up the third view530. In response to a CLD user clicking on the “previous” arrow, one ofthe link attributes 450 (FIG. 4) to style sheet 310 (FIGS. 3 and 4) isactivated, calling up the first view 510.

[0033] Referring to FIG. 5C, in response to the link 450 being activatedfrom the second view 520 (FIG. 5B), HTML document 360 is displayed onthe CLD display screen 110 in the second view 530. In this view 530, athird set of attributes previously not displayed in first view 510 orsecond view 520 are displayed along with the attributes common to thefirst and second views 510 and 520. For navigational purposes, in thethird view 530 the value for the current page number and total number ofpages is displayed, i.e., “page 3 of 3.” The view 530 also includes thelink 450 (FIG. 4) associated with the “previous” arrow to go back to thesecond view 520.

[0034] Referring to FIG. 6, a flow chart illustrating a method forrestyling a web page to an optimized web page is shown. In thisembodiment, the web page prepared for display on desktop display screen105 is used as an input to generate optimized web pages suitable fordisplay on a CLD having display screen 110.

[0035] In step 610, in response to receiving a request to restyle theweb page, first derivative XSLT style sheet file 310 describing firstpresentation style document 340 is generated. First derivative XSLTstyle sheet file 310 is derived from a first copy of Master XSLT stylesheet file 230. Master XSLT style sheet 230 specifies a style ofdisplaying information 100 included in the web page. Information 100includes a plurality of attributes, e.g., unique problem number 130,status 145, due date and time 150, severity 155, group user 160,location 165, contact/company 170 and problem description 175. Out ofthe plurality of attributes, first set of attributes 425 are included infirst derivative XSLT style sheet file 310.

[0036] In step 620, second derivative style sheet file 320 describingsecond presentation style document 350 is derived from a second copy ofmaster XSLT style sheet file 230. Second set of attributes 435 includedin information 100 are included in second derivative XSLT style sheetfile 320.

[0037] In step 630, first presentation style document 340 and secondpresentation style document 350 are generated by XSLT processor 220 onreceiving XML source document 210 describing information 100, firstderivative style sheet file 310 and second derivative style sheet file320 as inputs.

[0038] Referring to FIG. 7, a computer system 710 is shown that isgenerally applicable for the various embodiment described according tothe present invention. The system 710 includes a processor 715, avolatile memory 720, e.g., RAM, a keyboard 725, a pointing device 730,e.g., a mouse, a nonvolatile memory 735, e.g., ROM, hard disk, floppydisk, CD-ROM, and DVD, and a display device 705 having a display screen.Memory 720 and 735 are for storing a program instructions which areexecutable by processor 715 to implement various embodiments of a methodin accordance with the present invention. Components included in system710 are interconnected by bus 740. A communications device (not shown)may also be connected to bus 740 to enable information exchange betweensystem 710 and other devices.

[0039] In various embodiments system 710 takes a variety of forms,including a personal computer system, mainframe computer system,workstation, Internet appliance, PDA, an embedded processor with memory,etc. That is, it should be understood that the term “computer system” isintended to encompass any device having a processor that executesinstructions from a memory medium. The memory medium preferably storesinstructions (also known as a “software program”) for implementingvarious embodiments of a method in accordance with the presentinvention. In various embodiments the one or more software programs areimplemented in various ways, including procedure-based techniques,component-based techniques, and/or object-oriented techniques, amongothers. Specific examples include XML, C++objects, Java and MicrosoftFoundation Classes (MFC).

[0040] It should also be understood from the foregoing that in variousembodiments the method for publishing a web page optimized for a devicehaving a limited display screen is implemented in a variety ofprogramming languages, such as XML and XSLT. In one embodiment, themethod uses Java Server Pages (“JSP”), and, accordingly, a Javaprocessor receives one or more .jsp style sheet files to generate HTMLdisplays. In one embodiment, the method uses Visual Basic programminglanguage.

[0041] The description of the present embodiments have been presentedfor purposes of illustration, but are not intended to be exhaustive orto limit the invention to the forms disclosed. Many additional aspects,modifications and variations are also contemplated and are intended tobe encompassed within the scope of the following claims. For example,while certain aspects of the present invention have been described inthe context of a fully functioning data processing system, those ofordinary skill in the art will appreciate that the processes of thepresent invention are capable of being distributed in the form of acomputer readable medium of instructions in a variety of forms. Thepresent invention applies equally regardless of the particular type ofsignal bearing media actually used to carry out the distribution.Examples of computer readable media include RAM, flash memory,recordable-type media such as a floppy disk, a hard disk drive, a ROM,CD-ROM, DVD and transmission-type media such as digital and/or analogcommunication links, e.g., the Internet.

[0042] Although the embodiment described above has first and seconddocuments 340 and 350 for producing corresponding first and second viewson the limited device, as shown in FIGS. 3, 5A and 5B, in analternative, one document is produced having at least two frames. Forexample, frames are typically configured in a web display by using<FRAMESET>, </FRAMESET> commands. In this single-document embodiment, afirst frame that is vertically scrollable but not horizontallyscrollable displays problem number 130 (FIGS. 1, 5A, 5B and 5C). Asecond frame that is vertically scrollable in coordination with thefirst frame displays, and is also horizontally scrollable, displaysadditional attributes of service request records corresponding to therespectively displayed problem numbers. Accordingly, the terms “firstpresentation material” and “second presentation material” are usedherein to refer to first and second documents for generating first andsecond views on the CLD, as in the first embodiment, and also to referto a single document with the first and second frames, as in thesingle-document embodiment. Thus, for the single-document embodiment,“first presentation material” refers to the document with the firstframe and a first instance of the second frame, and “second presentationmaterial” refers to the document with the first frame and a secondinstance of the second frame.

[0043] Although certain aspects of the present invention have beendescribed in the context of application to a “connected, limiteddevice,” implying that the device is connected to a computer or networkof computers, it should be understood that the invention applies equallyto devices having limited size display screens but which are notconnected to a computer or network.

[0044] To reiterate, many additional aspects, modifications andvariations are also contemplated and are intended to be encompassedwithin the scope of the following claims. Moreover, it should beunderstood that in the following claims actions are not necessarilyperformed in the particular sequence in which they are set out.

What is claimed is:
 1. A method for creating multiple segments ofinformation for presentation on a device having a limited size displayscreen, the method comprising: generating a first derivative style sheetfile from a first copy of a master style sheet file specifying a styleof displaying source information, wherein the source informationcomprises a plurality of attributes and the first derivative style sheetfile has a first set of ones of the attributes of the sourceinformation; generating a second derivative style sheet file from asecond copy of the master style sheet file, wherein the secondderivative style sheet file has a second set of ones of the attributesof the source information; generating first presentation material inresponse to the source information and the first derivative style sheetfile; and generating second presentation material in response to thesource information and the second derivative style sheet file.
 2. Themethod of claim 1, wherein the source information specified by themaster style sheet exceeds an amount of information capable of beingdisplayed by the device in a single view, the source informationcomprising a first segment of information associated with the first setof attributes and a second segment of information associated with thesecond set of attributes, and wherein the first presentation material isfor generating a first view of the first segment on the device and thesecond presentation material is for generating a second view of thesecond segment on the device, the device being capable of concurrentlydisplaying, in the first view, all of the first segment of informationand concurrently displaying, in the second view, all of the secondsegment of information.
 3. The method of claim 1, wherein generating thefirst derivative style sheet comprises deleting at least a firstattribute from the plurality of attributes, the at least first attributebeing included in the second set of attributes.
 4. The method of claim1, wherein generating the first derivative style sheet comprises addinga link attribute referring to the second derivative style sheet, thelink attribute enabling navigation between a first segment ofinformation associated with the first set of attributes and a secondsegment of information associated with the second set of attributes. 5.The method of claim 1, wherein generating the second derivative stylesheet comprises deleting at least a second attribute from the pluralityof attributes, the at least second attribute being included the firstset of attributes.
 6. The method of claim 1, wherein generating thesecond derivative style sheet comprises adding a link attributereferring to the first derivative style sheet, the link attributeenabling navigation between the second segment of information associatedwith the second set of attributes and the second segment of informationassociated with the first set of attributes.
 7. The method of claim 1,wherein the first set of attributes and the second set of attributeshave at least one common attribute.
 8. The method of claim 1, wherein atleast one of the source information attributes is excluded from thefirst set of attributes and included in the second set of attributes,and at least one of the source information attributes is excluded fromthe second set of attributes and included in the first set ofattributes.
 9. A computer system comprising: a processor; and a memorycoupled to the processor, wherein the memory is enabled to store programinstructions, wherein the processor is operable to execute the programinstructions for: generating a first derivative style sheet file from afirst copy of a master style sheet file specifying a style of displayingsource information, wherein the source information comprises a pluralityof attributes and the first derivative style sheet file has a first setof ones of the attributes of the source information; generating a secondderivative style sheet file from a second copy of the master style sheetfile, wherein the second derivative style sheet file has a second set ofones of the attributes of the source information; generating firstpresentation material in response to the source information and thefirst derivative style sheet file; and generating second presentationmaterial in response to the source information and the second derivativestyle sheet file.
 10. The system of claim 9, wherein the sourceinformation specified by the master style sheet exceeds an amount ofinformation capable of being displayed by the device in a single view,the source information comprising a first segment of informationassociated with the first set of attributes and a second segment ofinformation associated with the second set of attributes, and whereinthe first presentation material is for generating a first view of thefirst segment on the device and the second presentation material is forgenerating a second view of the second segment on the device, the devicebeing capable of concurrently displaying, in the first view, all of thefirst segment of information and concurrently displaying, in the secondview, all of the second segment of information.
 11. The system of claim9, wherein generating the first derivative style sheet comprisesdeleting at least a first attribute from the plurality of attributes,the at least first attribute being included in the second set ofattributes.
 12. The system of claim 9, wherein generating the firstderivative style sheet comprises adding a link attribute referring tothe second derivative style sheet, the link attribute enablingnavigation between a first segment of information associated with thefirst set of attributes and a second segment of information associatedwith the second set of attributes.
 13. The system of claim 9, whereingenerating the second derivative style sheet comprises deleting at leasta second attribute from the plurality of attributes, the at least secondattribute being included the first set of attributes.
 14. The method ofclaim 9, wherein generating the second derivative style sheet comprisesadding a link attribute referring to the first derivative style sheet,the link attribute enabling navigation between the second segment ofinformation associated with the second set of attributes and the secondsegment of information associated with the first set of attributes. 15.The system of claim 9, wherein the first set of attributes and thesecond set of attributes have at least one common attribute.
 16. Thesystem of claim 9, wherein at least one of the source informationattributes is excluded from the first set of attributes and included inthe second set of attributes, and at least one of the source informationattributes is excluded from the second set of attributes and included inthe first set of attributes.
 17. A computer program product, forcreating multiple segments of information for presentation on a devicehaving a limited size display screen, the computer program producthaving program logic on a computer readable storage media for causing acomputer system to perform: generating a first derivative style sheetfile from a first copy of a master style sheet file specifying a styleof displaying source information, wherein the source informationcomprises a plurality of attributes and the first derivative style sheetfile has a first set of ones of the attributes of the sourceinformation; generating a second derivative style sheet file from asecond copy of the master style sheet file, wherein the secondderivative style sheet file has a second set of ones of the attributesof the source information; generating first presentation material inresponse to the source information and the first derivative style sheetfile; and generating second presentation material in response to thesource information and the second derivative style sheet file.
 18. Thecomputer program product of claim 17, wherein the source informationspecified by the master style sheet exceeds an amount of informationcapable of being displayed by the device in a single view, the sourceinformation comprising a first segment of information associated withthe first set of attributes and a second segment of informationassociated with the second set of attributes, and wherein the firstpresentation material is for generating a first view of the firstsegment on the device and the second presentation material is forgenerating a second view of the second segment on the device, the devicebeing capable of concurrently displaying, in the first view, all of thefirst segment of information and concurrently displaying, in the secondview, all of the second segment of information.
 19. The computer programproduct of claim 17, wherein generating the first derivative style sheetcomprises deleting at least a first attribute from the plurality ofattributes, the at least first attribute being included in the secondset of attributes.
 20. The computer program product of claim 17, whereingenerating the first derivative style sheet comprises adding a linkattribute referring to the second derivative style sheet, the linkattribute enabling navigation between a first segment of informationassociated with the first set of attributes and a second segment ofinformation associated with the second set of attributes.
 21. Thecomputer program product of claim 17, wherein generating the secondderivative style sheet comprises deleting at least a second attributefrom the plurality of attributes, the at least second attribute beingincluded the first set of attributes.
 22. The computer program productof claim 17, wherein generating the second derivative style sheetcomprises adding a link attribute referring to the first derivativestyle sheet, the link attribute enabling navigation between the secondsegment of information associated with the second set of attributes andthe second segment of information associated with the first set ofattributes.
 23. The computer program product of claim 17, wherein thefirst set of attributes and the second set of attributes have at leastone common attribute.
 24. The computer program product of claim 17,wherein at least one of the source information attributes is excludedfrom the first set of attributes and included in the second set ofattributes, and at least one of the source information attributes isexcluded from the second set of attributes and included in the first setof attributes.